The invention relates to a flush-fitted instrument cluster for a motor vehicle, with an electronic display device, such as an organic light emitting diode (OLED) display device, which emits imaging light and is positioned in the direct field of vision of a viewer, with at least one illuminated and/or self-luminous electromechanical display device, which is positioned at an angle to the electronic display in the field of vision of the viewer and which is movable (reflectable) into the field of vision of the viewer by means of an electromechanical display device for the imaging light with the reflecting optical combination device in addition or alternatively to the electronic display.
The amount of information displayed to a driver of a motor vehicle as a result of the growing number of comfort features, such as navigation equipment, telecommunication equipment, and driver support systems, which are available from the various selections, increases continuously. This is the reason why many vehicles already use so-called multifunction control units, which are located in the center console, for instance. With this type of layout, the driver has to take his eyes off the road in order to receive this information. For this reason, it is advantageous if at least part of this information can be displayed in the instrument cluster within the driver's field of vision.
In order to solve this problem by providing only a certain display surface in the instrument cluster in addition to the indicating gauges for speed, RPM, etc., a flush-fitted instrument cluster as mentioned at the outset was developed (German patent application 103 33 745.8, no prior publication). In this flush-fitted instrument cluster, the display device and the electromechanical display device are specifically arranged in relation to each other, so that they are always located within the viewer's field of vision. While the display device, which is provided in the form of a liquid crystal display, an OLED display or any other type of display, is physically located in the instrument panel of the vehicle within the viewer's field of vision, the electromagnetic display equipment, which has the indicating elements of a conventional instrument cluster, such as round gauges like speedometers, is arranged at an angle in relation to the electronic display, outside of the driver's field of vision. A multifunction device, preferably in the form of a semitransparent mirror, is positioned between the electronic display device and the electromechanical display device in such a way that it combines the imaging light of the electronic display device and the electromechanical display device as a consolidated display in the viewer's line of vision.
A flush-fitted instrument cluster of this type of design permits simultaneous or alternative display of the electronic display device and of the electromechanical display device. Due to the non-uniform contour geometry of the display device, which typically has a rectangular shape, and the electromechanical display device, which is designed preferably as a round gauge, and because of the different size of these devices, on the one hand, and due to the confined space of the installation sites of the instrument panel in the vicinity of the steering wheel of a vehicle, on the other, this results in an unavoidable, virtual position overlap of the reflected electromechanical display device and the electronic display device that are positioned in the viewer's field of vision. It was found that because of the difference in the brightness of the backgrounds of the electronic display devices and the combination device, a sudden unwanted jump in brightness between the overlapped backgrounds and a non-overlapping background section occurs during a virtual overlap of these devices.
The typical selected background color of electromechanical display devices, for example of a round gauge, is jet-black, i.e., essentially with a brightness of at least 0 candela per m2 (0 cd/m2). A display device, specifically one which is designed as an OLCD display, cannot represent a similar black background, due to design constraints, so that in case of a combined representation of the electronic display device and the electromechanical display device it produces overlapping between the lesser intense black background (brightness greater than 0 cd/m2) of the electronic display device and the jet-black background (0 cd/m2) of the mechanical display device, producing an unwanted jump in brightness between the overlapped surface areas of the background and the one non-overlapping surface area. Accordingly, a need exists for an improved instrument cluster for use in a motor vehicle.